The present invention relates to external rear view mirrors for vehicles and in particular to mirrors of the type having a head pivotally mounted to a base.
Vehicle external side rear view mirrors commonly comprise a mirror head which is pivotally attached to a mirror base or mounting bracket. The mounting bracket is in turn secured to the motor vehicle body. The pivot enables the mirror head to rotate with respect to the base if it is impacted either while the vehicle is moving or stationery (referred to as “mirror break away”). The pivot also enables the mirror head to move to a “park” position under the action of a drive means to effectively reduce the width of the vehicle and reduce the risk of impact or interference from passing pedestrians or other vehicles. The ability to “park” the mirror head also facilitates transportation of the vehicle.
Spring loaded detent systems are used in external rear vision mirrors on motor vehicles to provide the ability for the mirror head to be alternatively held in a deployed position and a parked or folded position.
A problem in the assembly of such spring loaded detent systems is that while a moving part (typically connected to the mirror head) and a fixed part (typically connected to the mirror base or bracket) are being assembled, a spring which loads the detent system must be held compressed. Such an operation usually requires special tooling to hold the spring in a loaded position during assembly. Furthermore, such an assembly operation can, in some cases, pose a danger to the assembler.
In order to limit the degree of rotation of the head with respect to the base, end stops are provided within the mirror assembly. A known simple end stop arrangement includes a projection fixed with respect to either the head or the base that engages a stop fixed with respect to either the base or the head. Such simple stop arrangements have the disadvantage that they cause twisting of the head with respect to the base. This twisting causes a shear load through the pivot axis.
Other end stop arrangements have the disadvantage that they limit the degree of travel of the head with respect to the base to less than 180°.
It is an object of the invention to provide a vehicle external mirror assembly that overcomes at least some of the above stated problems.
It is a further object of the invention to provide an improved pivot assembly for a vehicle external mirror that is adapted to pre-load a detent spring in a simple assembly operation not requiring any special tools or expertise.
It is a further object of the invention to provide a method for assembling a pivot assembly incorporating a spring-loaded detent system.